JP2018183829A - Cutting insert and manufacturing method of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cutting insert which can inhibit occurrence of chatter vibration.SOLUTION: A cutting insert 1 includes at least a first end surface 20 and a second end surface 21 facing each other, a periphery side surface 22 extending between the first end surface 20 and the second end surface 21 and has at least a first periphery side surface 30 and a second periphery side surface 31 located adjacent to the first periphery side surface 30, a cutting edge 41 formed in an edge line between the first end surface 20 and the first periphery side surface 30, and a smooth cutting surface 60 which is formed continuing into the cutting edge 41 on the first end surface 20. The first end surface 20 has a first surface area 80 including at least the smooth cutting surface 60; and a second surface area 81 different from the first surface area 80. Surface roughness Ra of the first surface area 80 is 0.3 μm or smaller, and surface roughness Ra of the second surface area 81 exceeds 0.3 μm.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a cutting insert and a manufacturing method thereof.

  In the cutting process such as post-grinding, grooving, and parting-off, a cutting tool equipped with a cutting insert is used. The cutting insert generally has two end faces facing each other in a polygonal shape and a peripheral side face connecting the two end faces. For example, the cutting insert is cut at a ridge line between the first end face and the first peripheral side face of the peripheral side face. A blade is formed. A chip breaker or the like for cutting normal chips is formed on the first end face (see Patent Documents 1, 2, and 3).

International Publication No. 2016/093275 JP-A-2005-153101 JP 2012-250296 A

  By the way, chips generated during cutting may damage the workpiece. Therefore, in order to form a highly accurate and clean machined surface, it is necessary to improve the chip treatment performance of the cutting insert. As a result, many cutting inserts in recent years have complicated shapes. Therefore, it is necessary to form this type of cutting insert using a sintering method capable of forming even a complicated shape.

  However, when the cutting insert is molded using a sintering method, the surface of the cutting insert is rough, so that chatter vibration is likely to occur between the cutting insert and the workpiece during cutting. When chatter vibration occurs, chatter (chatter marks) remains on the processed surface of the workpiece, which is not preferable.

  The present application has been made in view of such points, and an object thereof is to provide a cutting insert capable of suppressing the occurrence of chatter vibration and a method for manufacturing the same.

  A cutting insert according to an aspect of the present invention includes a first end surface and a second end surface facing each other, extending between the first end surface and the second end surface, and a first peripheral side surface; A peripheral side surface having at least a second peripheral side surface adjacent to the first peripheral side surface; a cutting edge formed on a ridge line between the first end surface and the first peripheral side surface; and the first end surface And at least a smooth rake face formed continuously with the cutting edge, wherein the first end face is different from the first surface area in a first surface area including at least the smooth rake face. The surface roughness Ra of the first surface region is 0.3 μm or less, and the surface roughness Ra of the second surface region exceeds 0.3 μm. The “smooth rake surface” is a surface processed so that the surface roughness is reduced by grinding or polishing, and includes not only a flat surface but also a curved surface.

  According to this aspect, the occurrence of chatter vibration can be suppressed by setting the surface roughness Ra of the first surface region including at least the smooth rake face to 0.3 μm or less.

A chip breaker is formed on the first end surface, and the chip breaker has at least the smooth rake surface and a non-smooth surface, and the non-smooth surface is included in the second surface region. May be. The non-smooth surface may include a recess of the chip breaker. Note that the “non-smooth surface” is a surface that has not been processed to reduce the surface roughness such as grinding or polishing.

  The cutting insert includes another cutting edge formed on a ridge line between the first end surface and the second peripheral side surface, and another smoothing formed continuously with the other cutting edge on the first end surface. A rake face, and the other smooth rake face may be included in the first surface region.

  The surface roughness Ra of the first peripheral side surface and the second peripheral side surface may be 0.4 μm or less.

  The difference in surface roughness Ra between the first surface region and the second surface region may be 0.2 μm or more.

  A boundary portion between the first surface region and the second surface region may be smoothly configured without irregularities.

  The angle difference between the surface of the first surface region and the surface of the second surface region in the boundary portion may be 30 ° or more and 45 ° or less.

  A cutting insert manufacturing method according to another aspect of the present invention includes a first end surface and a second end surface facing each other, extending between the first end surface and the second end surface, A peripheral side surface, a peripheral side surface having at least a second peripheral side surface adjacent to the first peripheral side surface, a cutting edge formed on a ridge line between the first end surface and the first peripheral side surface, A method of manufacturing a cutting insert having at least a smooth rake face formed continuously on the cutting edge at a first end face, the step of forming the cutting insert by a sintering method, and the first And grinding or polishing the first surface region including at least the smooth rake face at the end surface of the first surface region, the surface roughness Ra of the first surface region being 0.3 μm or less, Different from the first surface region at the end face of The surface roughness Ra of the second surface region to exceed 0.3 [mu] m.

  In the cutting insert manufacturing method, a chip breaker is formed on the first end surface, and the chip breaker includes at least the smooth rake surface and a non-smooth surface, and the non-smooth surface includes the first end surface. It may be included in the two surface regions. The non-smooth surface may include a recess of the chip breaker.

  The cutting insert is continuous with the other cutting edge formed on the ridge line between the first end surface and the second peripheral side surface, and the other cutting edge on the first end surface. The other smooth rake face formed may be further included, and the other smooth rake face may be included in the first surface region.

  The manufacturing method of the cutting insert further includes a step of grinding or polishing the first peripheral side surface and the second peripheral side surface, and the surface roughness of the first peripheral side surface and the second peripheral side surface. Ra may be 0.4 μm or less.

  The difference in surface roughness Ra between the first surface region and the second surface region may be 0.2 μm or more.

  A boundary portion between the first surface region and the second surface region may be smoothly configured without irregularities.

  The angle difference between the surface of the first surface region and the surface of the second surface region in the boundary portion may be 30 ° or more and 45 ° or less.

It is a perspective view of a cutting tool. It is a perspective view of a cutting insert. It is a right view seen from the 2nd peripheral side of a cutting insert. It is the front view seen from the 1st end surface of the cutting insert. It is an enlarged view around the 1st cutting edge and the 2nd cutting edge of a cutting insert. It is an enlarged view which shows the 1st cutting edge and 2nd cutting edge of the cutting insert seen from the 1st end surface side. It is XX sectional drawing of FIG. It is YY sectional drawing of FIG. It is explanatory drawing which shows the chip breaker of a cutting insert. It is explanatory drawing which shows the mode of the post-grinding process using the cutting insert. It is a table | surface which shows a test result.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. In addition, the same code | symbol is attached | subjected to the same element and the overlapping description is abbreviate | omitted. Further, the positional relationship such as up, down, left and right is based on the positional relationship shown in the drawings unless otherwise specified. Furthermore, the dimensional ratios in the drawings are not limited to the illustrated ratios. Moreover, the following embodiment is an illustration for explaining the present invention, and the present invention is not limited to this embodiment.

  FIG. 1 is a perspective view showing a cutting tool 2 equipped with a cutting insert 1 according to the present embodiment. The cutting tool 2 includes an elongated and columnar tool body 10 that is long in one direction, and a cutting insert 1 that is attached to the tip of the tool body 10. The cutting insert 1 is fixed to the tool body 10 by a clamp member (clamping screw) 11.

  2 is a perspective view of the cutting insert 1, FIG. 3 is a right side view of the cutting insert 1 as viewed from the second peripheral side surface, and FIG. 4 is a front view of the cutting insert 1 as viewed from the first end surface. FIG. The cutting insert 1 is for, for example, post-grinding of an automatic lathe. The cutting insert 1 has a substantially polygonal shape, for example, a plate shape having a substantially rectangular thickness. The cutting insert 1 has, for example, a length L of about 25 mm, a width W of about 2.5 mm, and a height H of about 11 mm. The material of the cutting insert 1 is not particularly limited. For example, a hard material such as cemented carbide, cermet, ceramics, and sintered body containing cubic boron nitride, or the surface of these hard materials is PVD or CVD coated. It is selected from those coated with a film, or single crystal diamond or a sintered body containing diamond.

  The cutting insert 1 includes a first end surface 20 and a second end surface 21 that face each other, and a peripheral side surface 22 that extends between the first end surface 20 and the second end surface 21.

  The peripheral side surface 22 consists of four peripheral side surfaces, for example. The cutting insert 1 has a first peripheral side surface 30, a second peripheral side surface 31, a third peripheral side surface 32, and a fourth peripheral side surface 33 around the cutting insert 1 in this order as the peripheral side surface 22. The first peripheral side surface 30 and the second peripheral side surface 31, and the third peripheral side surface 32 and the fourth peripheral side surface 33 are symmetrical about the peripheral side surface of the cutting insert 1 and have the same configuration. . Hereinafter, the peripheral side surface 22 will be described by taking the first peripheral side surface 30 and the second peripheral side surface 31 as an example. However, the third peripheral side surface 32 has the same configuration as the first peripheral side surface 30, The peripheral surface 33 of 4 has the same configuration as that of the second peripheral surface 31.

  As shown in FIGS. 2 and 5, a first ridge line 40 is formed between the first end face 20 and the first peripheral side face 30, and a first cutting edge 41 is formed on the first ridge line 40. Is formed. A second ridge line 50 is formed between the first end surface 20 and the first peripheral side surface 30, and a third ridge line 51 is formed between the first end surface 20 and the second peripheral side surface 31. Is formed. A second cutting edge 52 as another cutting edge is formed on the second ridge line 50. The first cutting edge 41 and the second cutting edge 52 are formed continuously from the intersection 53 of the third ridge line 51 and the first ridge line 40 along the first ridge line 40 and the second ridge line 50. Yes. The length of the first cutting edge 41 is, for example, about 0.4 mm, and the length of the second cutting edge 52 is, for example, about 3.7 mm.

  As shown in FIG. 6, when viewed from the first end face 20 side, the angle C formed by the first cutting edge 41 and the third ridge line 51 is the angle D formed by the second cutting edge 52 and the third ridge line 51. It is formed larger than.

  A chip breaker 62 including a smooth rake face 60 and a smooth rake face 61 is formed on the first end face 20.

  The smooth rake face 60 is provided around the first cutting edge 41 so as to follow the first cutting edge 41, and is formed continuously with the first cutting edge 41. As shown in FIG. 7, the smooth rake face 60 is inclined so as to gradually decrease as the distance from the first cutting edge 41 increases. The rake angle A of the smooth rake face 60 (a positive angle made with the horizontal plane when the second end face 21 is assumed to be a horizontal plane) is set to about 20 °. The width F1 of the smooth rake face 60 is set to about 0.25 mm, for example.

  As shown in FIG. 6, the smooth rake face 61 is provided along the second cutting edge 52 around the second cutting edge 52, and is formed continuously from the second cutting edge 52. As shown in FIG. 8, the smooth rake face 61 is inclined so as to gradually decrease as the distance from the second cutting edge 52 increases. The rake angle B of the smooth rake face 61 (a positive angle with the horizontal plane when the second end face 21 is assumed to be a horizontal plane) is set to about 20 °. The width F2 of the smooth rake face 61 is set to about 0.35 mm, for example.

  As shown in FIGS. 2 and 9, the chip breaker 62 is formed in a groove shape along the first cutting edge 41 and the second cutting edge 25. The chip breaker 62 has a smooth rake surface 60, a smooth rake surface 61, and a non-smooth surface 63 (sintered skin surface) continuous with these smooth rake surfaces 60, 61. The shape of the chip breaker 62 is not particularly limited. For example, the chip breaker 62 has a recess 65 that is continuous with the smooth rake surfaces 60 and 61 and is recessed with respect to the smooth rake surfaces 60 and 61. Becomes a non-smooth surface 63. A groove wall surface 70 is formed on the third ridge line 51 side of the recess 65, and a height E (shown in FIG. 8) of the groove wall surface 70 with respect to the second cutting edge 52 is set to about 0.3 mm. Yes.

  As shown in FIG. 9, the first peripheral side surface 30 includes a first surface region 80 formed by grinding and a second surface region 81 formed by a sintering method. The first surface region 80 includes a smooth rake face 60 and a smooth rake face 61. The second surface region 81 includes a non-smooth surface 63 and a portion 64 other than the chip breaker 62.

  The surface roughness Ra of the first surface region 80 is 0.3 μm or less, preferably 0.2 μm or less. The surface roughness Ra of the second surface region 81 exceeds 0.3 μm. For example, the difference in surface roughness Ra between the first surface region 80 and the second surface region 81 is 0.2 μm or more.

  Further, the boundary portion between the first surface region 80 and the second surface region 81 is smoothly formed without a step. For example, the angle difference between the surface of the first surface region 80 and the surface of the second surface region 81 at the boundary is set to 45 ° or less, preferably 30 ° to 45 °. Specifically, for example, as shown in FIG. 7, the angle formed by the angle difference G between the smooth rake surface 60 of the chip breaker 62 and the inclined surface 90 of the recess 65 of the non-smooth surface 63 is set to about 40 °. . When the smooth rake surface 60 and the inclined surface 90 are curved surfaces, the angle difference G is defined as the angular difference between the tangent lines of the smooth rake surface 60 and the inclined surface 90 at the boundary.

  In addition to the first end 20, the first peripheral side surface 30 and the second peripheral side surface 31 shown in FIG. 2 are ground or polished, and have a surface roughness Ra of 0.4 μm or less. The first peripheral side surface 30 serves as a flank surface. A through hole 100 for the clamp member 11 that penetrates from the second peripheral side surface 31 to the fourth peripheral side surface 33 is formed in the center of the cutting insert 1.

  The cutting insert 1 configured as described above is manufactured as follows. First, the outer shape of the cutting insert 1 is formed by pressing and sintering the material. At this time, the outer surface of the cutting insert 1 is a sintered surface, and the surface roughness Ra exceeds 0.3 μm. Next, the smooth rake surfaces 60 and 61 in the first end face 20 are ground or polished to form the first surface region 80, and the surface roughness Ra is set to 0.3 μm or less. Moreover, the 1st surrounding side surface 30 and the 2nd surrounding side surface 31 are ground or grind | polished, and the surface roughness Ra is made into 0.4 micrometer or less. The first end face 20 may be ground or polished after the second peripheral side face 30 and the second peripheral side face 31 are ground or polished.

  Further, in the manufacturing method of the cutting insert 1, the carbide, nitride, oxide, carbonitride, carbonate, carbonitride, boronitride of the periodic table 4A, 5A, 6A group metals by CVD method, PVD method, etc. The surface of the cutting insert 1 may be coated with a peritoneum or the like selected from the group consisting of a material, borocarbonitride, aluminum oxide and titanium aluminum nitride. This coating process may be performed before the first end face 20 is ground or polished, or may be performed after the first end face 20 is ground or polished. When the coating process is performed after the first end face 20 is ground or polished, the first surface area 80 after the coating process has a surface roughness Ra of 0.3 μm or less. The end face 20 is ground or polished and is coated.

  Similarly, the above-described coating process may be performed before grinding or polishing the first peripheral side surface 30 and the second peripheral side surface 31, or grinding or polishing the first peripheral side surface 30 and the second peripheral side surface 31. It may be performed after polishing. When the coating process is performed after grinding or polishing the first peripheral side face 30 and the second peripheral side face 31, the final surface roughness of the first peripheral side face 30 and the second peripheral side face 31 after the coating process is performed. The first peripheral side surface 30 and the second peripheral side surface 31 are ground or polished and coated so that the thickness Ra is 0.4 μm or less.

  As shown in FIG. 1, the cutting insert 1 is attached to the tool body 10 by inserting a tightening screw 11 into the through hole 100 and tightening with the clamp member 11. In addition, the fixing method of this cutting insert 1 is not specifically limited, You may fix with a presser piece or a wedge. At the time of post-grinding, the workpiece 110 is fixed to a lathe chuck as shown in FIG. 10 and rotated around a horizontal axis. Then, the first cutting edge 41 side of the cutting insert 1 is brought close to the workpiece 110, and the workpiece 110 is cut in the radial direction by the first cutting edge 41 and cut. Thereafter, the cutting insert 1 is moved in the lateral direction (direction away from the chuck), and the workpiece 110 is cut in the longitudinal direction by the second cutting edge 52. As a result, the chuck-side end surface 110a and the outer peripheral surface 110b of the workpiece 110 are processed.

  According to the present embodiment, the first end face 20 has the first surface area 80 including at least the smooth rake face 60 of the first cutting edge 41 and the second surface area 81, The surface roughness Ra of the surface region 80 is 0.3 μm or less, and the surface roughness Ra of the second surface region 81 exceeds 0.3 μm. By carrying out like this, the cutting resistance (friction resistance) of the cutting insert 1 can reduce, and generation | occurrence | production of chatter vibration can be suppressed.

  Moreover, by smoothing the smooth rake face 60 and reducing the surface roughness, the dimensional accuracy of the cutting process by the cutting insert 1 is increased, and the stability of the processed dimension can be improved. In particular, in the processing of small-diameter parts by an automatic lathe, the surface roughness of the cutting insert 1 affects the processing accuracy, which is more effective. Moreover, since the dispersion | variation in the dimension of the cutting insert 1 becomes small by giving processes, such as grinding, to the smooth rake face 60, when the use corner of the cutting insert 1 is replaced | exchanged or the cutting insert 1 is replaced | exchanged, The machining shape will not vary.

  Since the non-smooth surface 63 of the chip breaker 62 is included in the second surface region 81 and the entire chip breaker 62 is not ground, the chip breaker 62 having a complicated shape can be realized by a sintering method. Therefore, the degree of freedom of the shape of the chip breaker 62 is increased, and the cutting insert 1 having a high chip processing capability can be realized.

  Since the smooth rake face 61 of the second cutting edge 52 is included in the first surface region 80 and is ground and the surface roughness Ra is 0.3 μm or less, the cutting resistance (friction resistance) of the cutting insert 1 is reduced. Furthermore, it can reduce and can suppress generation | occurrence | production of chatter vibration.

  The second peripheral side surface 31 forms a ridge line of the second cutting edge 52, and the first peripheral side surface 30 forms a ridge line of the first cutting edge 41. Since the second peripheral side surface 31 and the first peripheral side surface 30 are also ground and the surface roughness Ra is set to 0.4 μm or less, the dimensional accuracy of the cutting process of the cutting insert 1 is further increased, and the stability of the processing dimension is increased. Can be improved.

  Since the boundary portion between the first surface region 80 and the second surface region 81 is smoothly formed without irregularities, even if the first surface region 80 is ground, chip discharge at the boundary portion is obstructed. Such a step is not formed, and the chip processing capability of the cutting insert 1 can be secured.

  Since the angle difference between the surface of the first surface region and the surface of the second surface region at the boundary between the first surface region 80 and the second surface region 81 is not less than 30 ° and not more than 45 °, the angle difference is It is small and the processing capacity of chips can be suitably secured. In addition, since the angle difference is 30 ° or more, for example, the first surface region 80 such as the smooth rake surface 60 is not etched without grinding the second surface region 81 such as the non-smooth surface 63 of the chip breaker 62 with a grindstone. The grinding process can be suitably performed.

  The preferred embodiments of the present invention have been described above with reference to the accompanying drawings, but the present invention is not limited to such examples. It is obvious for those skilled in the art that various modifications or modifications can be conceived within the scope of the idea described in the claims, and these naturally belong to the technical scope of the present invention. It is understood.

  For example, in the above embodiment, the shape, length, angle, etc. of the first cutting edge 41 and the second cutting edge 52 are not limited thereto. The rake angle A of the smooth rake face 60 of the first cutting edge 41 and the rake angle B of the smooth rake face 61 of the second cutting edge 52 are the same, but the rake angle A is larger than the rake angle B. The rake angle A may be smaller than the rake angle B. In the above embodiment, the honing surface is not formed on the cutting insert 1, but a honing surface may be formed. The honing surface may be formed on the first cutting edge 41 and the second cutting edge 52, and the shapes of the honing surfaces may be different from each other.

  In the above embodiment, the first surface region 80 is the smooth rake surface 60 and the smooth rake surface 61, but other portions of the first end surface 20 are also ground or polished to form the first surface region 80. Also good. The second surface region 81 is a portion other than the smooth rake face 60 and the smooth rake face 61, but is not limited thereto. In the above embodiment, the first peripheral side surface 30 and the second peripheral side surface 31 other than the first end surface 20 are also ground or polished. However, the first peripheral side surface 30 and the second peripheral side surface 31 are The surface roughness Ra may be more than 0.4 μm without grinding. Moreover, you may grind | polish or grind other parts other than the 1st surrounding side surface 30 and the 2nd surrounding side surface 31 of the cutting insert 1. FIG.

  Although the cutting tool 2 in the above embodiment was a vertical insert type, the present invention can be applied to a flat type. The cutting insert 1 described in the above embodiment has two sets of cutting edges 41 and 52 (a set of the first end surface 20, the first peripheral side surface 30 and the second peripheral side surface 31, and a second combination). The end surface 21, the third peripheral side surface 32, and the fourth peripheral side surface 33) are formed, but may be one set or three or more sets. The outer shape of the cutting insert 1 is not limited to a square shape, and may be a triangular shape, a pentagonal shape, or the like. Although the cutting insert 1 described in the present embodiment is for post-grinding, the present invention is not limited to this, and may be for grooving or parting-off. In such a case, the cutting edge may be only the first cutting edge.

  A test was conducted to check the occurrence of chattering (chatter marks) on the workpiece by changing the surface roughness of the smooth rake face 60. The test conditions are as follows. The material of the workpiece is carbon steel (S45C), the machining diameter is 3 mm, the machining length is 10 mm, the cutting conditions are wet cutting (water-soluble cutting oil), and the maximum depth of cut ap = 1.5 mm, feed f = 0.1 mm / rev. The surface roughness Ra of the smooth rake face was varied between 0.2 and 0.7 μm. The test results are shown in FIG. When chatter did not occur in 5 tests, evaluation A, and when chatter occurred 1 to 4 times in 5 tests, evaluation B, and when chatter occurred 5 times in 5 tests Was evaluated as C.

  The present invention is useful in providing a cutting insert capable of suppressing the occurrence of chatter vibration and a method for manufacturing the same.

DESCRIPTION OF SYMBOLS 1 Cutting insert 2 Cutting tool 20 1st end surface 21 2nd end surface 30 1st surrounding side surface 31 2nd surrounding side surface 41 1st cutting edge 52 2nd cutting edge 60 Smooth rake face 61 Smooth rake face 62 Tip Breaker 80 First surface region 81 Second surface region

Claims (16)

A first end surface and a second end surface facing each other;
A peripheral side surface extending between the first end surface and the second end surface, and having at least a first peripheral side surface and a second peripheral side surface adjacent to the first peripheral side surface;
A cutting edge formed on a ridge line between the first end surface and the first peripheral side surface;
A smooth rake face formed continuously from the cutting edge at the first end face,
The first end face has a first surface area including at least the smooth rake face, and a second surface area different from the first surface area,
The surface roughness Ra of the first surface region is 0.3 μm or less;
A cutting insert in which the surface roughness Ra of the second surface region exceeds 0.3 μm. A chip breaker is formed on the first end surface,
The chip breaker has at least the smooth rake surface and a non-smooth surface,
The cutting insert according to claim 1, wherein the non-smooth surface is included in the second surface region.   The cutting insert according to claim 2, wherein the non-smooth surface includes a recess of the chip breaker. Another cutting edge formed on a ridge line between the first end surface and the second peripheral side surface;
Another smooth rake face formed continuously with the other cutting edge at the first end face,
The cutting insert according to any one of claims 1 to 3, wherein the other smooth rake face is included in the first surface region.   The cutting insert in any one of Claims 1-4 whose surface roughness Ra of a said 1st surrounding side surface and a said 2nd surrounding side surface is 0.4 micrometer or less.   The cutting insert according to any one of claims 1 to 5, wherein a difference in surface roughness Ra between the first surface region and the second surface region is 0.2 µm or more.   The cutting insert according to any one of claims 1 to 6, wherein a boundary portion between the first surface region and the second surface region is smoothly configured without irregularities.   The cutting insert according to claim 7, wherein an angle difference between a surface of the first surface region and a surface of the second surface region at the boundary portion is 30 ° or more and 45 ° or less. A first end surface and a second end surface facing each other;
A peripheral side surface extending between the first end surface and the second end surface, and having at least a first peripheral side surface and a second peripheral side surface adjacent to the first peripheral side surface;
A cutting edge formed on a ridge line between the first end surface and the first peripheral side surface;
A method for producing a cutting insert comprising at least a smooth rake face formed continuously from the cutting edge at the first end face,
Forming a cutting insert by a sintering method;
Grinding or polishing the first surface region including at least the smooth rake face in the first end face, and
The surface roughness Ra of the first surface region is set to 0.3 μm or less, and the surface roughness Ra of the second surface region different from the first surface region on the first end surface exceeds 0.3 μm. A method for manufacturing a cutting insert. A chip breaker is formed on the first end surface,
The chip breaker has at least the smooth rake surface and a non-smooth surface,
The method for manufacturing a cutting insert according to claim 8, wherein the non-smooth surface is included in the second surface region. The manufacturing method of the cutting insert of Claim 10 with which the recessed part of the said chip breaker is contained in the said non-smooth surface. The cutting insert has another cutting edge formed at a ridge line between the first end surface and the second peripheral side surface, and another cutting edge formed continuously with the other cutting edge at the first end surface. A smooth rake face, and
The method of manufacturing a cutting insert according to any one of claims 9 to 11, wherein the other smooth rake face is included in the first surface region. Grinding or polishing the first peripheral side surface and the second peripheral side surface;
The manufacturing method of the cutting insert in any one of Claims 9-12 which sets surface roughness Ra of a said 1st surrounding side surface and a said 2nd surrounding side surface to 0.4 micrometer or less.   The manufacturing method of the cutting insert in any one of Claims 9-13 whose difference of surface roughness Ra of a said 1st surface area and a said 2nd surface area is 0.2 micrometer or more.   The manufacturing method of the cutting insert in any one of Claims 9-14 with which the boundary part of the said 1st surface area and the said 2nd surface area is smoothly comprised without an unevenness | corrugation.   The manufacturing method of the cutting insert of Claim 15 whose angle difference of the surface of the 1st surface area in the said boundary part and the surface of a 2nd surface area is 30 degrees or more and 45 degrees or less.